Mulch Calculator
Mulch calculator: how much mulch, topsoil or gravel your garden beds need, in cubic yards, cubic feet and bags. Free, no sign-up, and it runs in your browser.
Dedicated page: /en/mulch-calculator
Default checked 10 Nov 2026: $40 per cubic yard (bulk hardwood $30 to $50). Leave it, or enter your exact price if you know it. Check the current value here.
Default checked 10 Nov 2026: $4 per bag (bagged mulch $3 to $7 per 2 cu ft bag). Leave it, or enter your exact price if you know it. Check the current value here.
Quick answer
A mulch calculator works out how much mulch, topsoil or gravel a garden bed needs. Add up the beds by length and width, pick a depth, and it gives the volume in cubic yards and cubic feet, the number of 2 cubic foot bags, and the bulk and bagged prices.
About this Mulch Calculator
Mulch calculator: how much mulch, topsoil or gravel your garden beds need, in cubic yards, cubic feet and bags. It is one of the Home and DIY on ToolUstad, and like every tool here it runs entirely in your browser: nothing you type, paste or open is uploaded to a server, and there is no sign-up or usage limit.
What is a mulch calculator?
Mulch is sold by the cubic yard in bulk and by the 2 cubic foot bag in stores, and the two units make comparison hard. One cubic yard is 27 cubic feet, which is 13.5 bags of 2 cubic feet. Bulk delivery is usually about half the price per yard of bagged mulch, but it needs a driveway to dump on, while bags can be carried to the back garden one at a time. The calculator gives both figures from the same bed measurements, so the choice is a price comparison, not a guess.
The depth matters as much as the area. Two inches is a top-up for beds that already have mulch. Three inches is the standard for weed control and moisture, and it is what most gardeners aim for. Four inches suits new beds and serious weed problems, but mulch piled deeper than 4 inches can suffocate the soil underneath. The calculator covers all three depths, and it handles topsoil and gravel the same way, because the volume maths is identical and only the material changes.
How does mulch maths work?
Two beds, one 10 by 4 feet and one 8 by 3 feet, total 64 square feet. At 3 inches deep, which is a quarter of a foot, the volume is 64 times 0.25, which is 16 cubic feet. Divide by 27 and that is 0.59 cubic yards. Divide by 2 and that is 8 bags of 2 cubic feet. At $40 a cubic yard, bulk costs about $24. At $4 a bag, bagged costs $32. The bulk saving grows with the job: on ten cubic yards, bulk can save hundreds of dollars.
When and why to use a mulch calculator
- Spring garden refresh: top up every bed at once, and order the whole lot in one delivery.
- New beds: a new bed needs the full 3 to 4 inch depth from bare soil, which is far more volume than a top-up.
- Comparing bulk and bags: the crossover is usually around 2 cubic yards, above which bulk delivery wins.
- Topsoil and gravel jobs: the same maths prices a raised bed fill or a gravel path.
- Checking a landscaper's quote: knowing the cubic yards yourself shows whether the quote has padded the materials.
Best practices
- Measure each bed separately and add them up, because one big rectangle always overestimates an irregular garden.
- Keep mulch 2 to 3 inches away from tree trunks and plant stems, because mulch piled against bark rots it.
- Water the beds before mulching, so the mulch locks the moisture in instead of keeping it out.
Common mistakes to avoid
- Forgetting that mulch settles about 10% in the first month: a 3 inch layer ends up near 2.7 inches, so top up again in spring.
- Ordering by the bag for a big job: 13.5 bags per yard means a 5 yard job is 68 bags to carry, load and open.
- Piling mulch into a volcano around trees: it looks tidy and kills the tree, because the bark stays wet and rots.
Who is the mulch calculator for?
Homeowners refreshing garden beds, landscapers pricing a job, and anyone filling a raised bed or laying a gravel path. It is also used by garden centre staff for counter estimates. The tool is an estimator: bed shapes are irregular and depths vary, so round up rather than down.
Current values, checked 10 Nov 2026: the defaults are $40 per cubic yard for bulk (hardwood $30 to $50) and $4 per 2 cu ft bag (bagged mulch $3 to $7). Both price boxes are optional overrides: leave the defaults, or enter your exact prices and the cost uses them.
Learn: how to use the Mulch Calculator
- Add one bed per row with its length and width in feet. The two default beds are an example: change them or remove them.
- Pick the depth: 2 inches to top up, 3 inches as standard, 4 inches for new beds and weed control.
- Read the cubic yards and bag count, then compare the bulk price against buying bags.
Features
- Multiple beds added up into one total
- Depth from 2 to 4 inches, with coverage per cubic yard shown
- Mulch, topsoil and gravel modes in one tool
- Cubic yards, cubic feet and 2 cubic foot bag counts
- Bulk versus bagged cost comparison so you buy the cheaper way
Worked example
Two beds, 10 by 4 feet and 8 by 3 feet, at 3 inches deep: 64 sq ft times 0.25 feet is 16 cubic feet, or 0.59 cubic yards, which is 8 bags of 2 cu ft. Bulk at $40 a yard costs about $24, against $32 for bags.
Frequently asked questions
How deep should mulch be?
3 inches is the standard for weed control and moisture. 2 inches is enough for a yearly top-up, and 4 inches suits new beds, but never pile mulch against tree trunks or plant stems.
How many bags make a cubic yard?
13.5 bags of 2 cubic feet make one cubic yard (27 cubic feet divided by 2). Bags are handy for small jobs; bulk delivery is usually half the price per yard for bigger ones.
What is the difference between mulch and topsoil?
Mulch sits on top to hold moisture and block weeds. Topsoil is the growing layer underneath, used to raise bed levels or fill low spots. This tool calculates volume the same way for both.
Does mulch settle?
Yes, about 10% in the first month as it compacts and breaks down. A 3 inch layer ends up near 2.7 inches, which is why most gardeners top up every spring.
How much does a cubic yard of mulch cover?
100 square feet at 3 inches deep, 162 square feet at 2 inches, and 81 square feet at 4 inches. One cubic yard is 27 cubic feet.
Is bulk mulch cheaper than bags?
Almost always, by about half per cubic yard. Bags win only for tiny jobs, or where a truck cannot reach the garden to dump the load.
How often should I replace mulch?
Top it up every spring, because it breaks down into the soil over a year. A full replacement is rarely needed: the old mulch becomes soil, and the new layer goes on top.
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